A new aberration-corrected, energy-filtered LEEM/PEEM instrument. I. Principles and design

Doping profile of InP nanowires directly imaged by photoemission electron microscopy

“…We are, therefore, not limited by the instrumental resolution which is typically a few tens of nm in XPEEM. 22 We use the lengths of the SCRs to estimate carrier concentration in the undoped segment. It is generally found that undoped InP NWs have a slight n-type doping.…”

Addendum. Laplacian image contrast in mirror electron microscopy

“…It is a subset of non-parallel MEM specimen illumination considered in the literature (Barnett & Nixon 1967a;Luk'yanov et al 1974;Someya & Kobayashi 1974;Dupuy et al 1984;Godehardt 1995). Modern low energy electron microscopes (LEEMs) are, however, equipped with a magnetic objective lens and it is customary to slightly converge the incident illumination to compensate for the diverging effect of the anode aperture, resulting in collimated illumination of the sample (Altman 2010;Tromp et al 2010), within the domain of validity of the aperture lens approximation. This paper therefore considers how MEM Laplacian imaging theory (Kennedy et al 2010) is modified by a parallel or collimated illumination geometry.…”

Diamondoid coating enables disruptive approach for chemical and magnetic imaging with 10 nm spatial resolution

“…Because of its element, chemical and spin structure specificity it is used by researchers from a variety of disciplines for composition mapping and analysis [12][13][14][15][16][17][18] . However, the photoexcited electrons from the sample surface tend to have a broad energy distribution, limiting the spatial resolution to 25 nm or more due to chromatic aberration within the electron lens system 19,20,21,22 . This puts X-PEEM at a disadvantage when compared to related techniques such as X-ray transmission or diffraction microscopy 23,24 .…”

“…Ultraviolet excitation could be used to limit the energy spread to 1 eV or less to obtain 10 nm spatial resolution 19 , however at the cost of elemental, chemical and magnetic sensitivity. Another approach is to introduce corrective electron optics into the microscope 19,20,21,22 . However, this comes at significant costs (>$1M) compared to conventional PEEM (~$100k) and makes the operation much more complex.…”

“…To limit the effects of chromatic aberration of the lens system an aperture is typically mounted in the back focal plane of the objective lens that rejects 90% or more of the electrons but at the same time reduces the effect of chromatic aberrations 20,21 . Using apertures with a diameter of 10 -20 m one can achieve a spatial resolution of about 25 nm 19,22 , while still maintaining practical image intensity.…”